The ongoing Volkswagen diesel scandal continues to affect the U.S. market for diesel cars in a negative way.

Diesels have never been as popular in the U.S. as they are in Europe, and models on offer have typically been limited to VW Group brands and a smattering of other German makers.

No VW Group brand is currently selling diesels in the U.S., meaning Audi, Porsche, and VW itself are out of the game, very possibly forever.

DON'T MISS: Diesel cars dwindle as Mercedes-Benz C300d is pulled from U.S. before launch

The scandal has also tested the resolve of Mercedes-Benz, which is now asking whether U.S. diesels are worth the effort.

The German luxury automaker is seeking EPA certification for a limited number of diesel models, but is also considering dropping diesels entirely for North America, reports industry trade journal Automotive News (subscription required).

Mercedes is now conducting market research to determine whether it is worthwhile to continue selling diesels in the U.S., Matthias Luehrs—Mercedes-Benz Cars' vice president of sales and product management—said during an interview at last week's Los Angeles Auto Show.

2017 Mercedes-Benz GLS Class

2017 Mercedes-Benz GLS Class

Dropping diesels from the U.S. market is a "theoretical option," Luehrs said.

Mercedes expects the first batch of results from its diesel market research early next year, he said, noting that North American demand for diesels is low and "still lowering."

The automaker will prioritize certification of the GLS350d three-low large SUV, and will also try to get diesel versions of its smaller GLC and mid-size GLE utility vehicles certified.

However, Mercedes recently announced that it would not sell the C300d 4Matic sedan in the U.S.

The C300d was originally slated to go on sale here in the first quarter of 2016, but never made it into U.S. showrooms.

But while Mercedes is considering elimination of its U.S. diesel lineup, Audi is mulling a return to diesel sales—although perhaps with just a single model.

2017 Audi Q7

2017 Audi Q7

That vehicle would be a TDI diesel version of the Q7 SUV, its largest utility vehicle, Audi of America president Scott Keogh told Reuters in an interview at the Los Angeles Auto Show.

He also said that diesel was "always a bridge technology" that would be useful only until emissions standards got tougher.

It should be noted that Audi and its Volkswagen Group parent lobbied to get diesels the same regulatory perks as hybrids and electric cars.

But even if Audi begins selling diesel vehicles in the U.S. again, the Volkswagen brand likely will not.

2016 Volkswagen Passat SEL long-term test

2016 Volkswagen Passat SEL long-term test

At the Los Angeles Auto Show, VW Group of America CEO Hinrich Woebcken said diesel would never "come back in the same magnitude as we've seen it up to now" in the U.S.

Diesels previously made up as much as 25 percent of the Volkswagen brand's U.S. sales.

But following that declaration, Volkswagen brand boss Herbert Diess told Reuters flat out that the automaker will no longer sell diesels in the U.S. at all.

"Emissions standards in the following years are getting tougher and tougher," Woebcken said, indicating that continued efforts to make diesels compliant with these regulations would be a wasted effort.


Follow GreenCarReports on Facebook and Twitter